Lesson Plan # 10 - Introduction to Negative numbers and the number line

  1. (5 min) Mental Math
    1. Start with 18, subtract 13, then multiply by 3 [15]
    2. Multiply 50 by 30 [1500]
    3. Multiply one-half times one-half times one-half [1/8]
    4. What is the area of a triangle whose base is 1/2 inch and whose height is 1/2 inch? [1/8 sq. in.]
    5. What is .5 times .5? [.25]

  2. (15 min) Give students the Progress Quiz (no review today)
    Progress Quiz Scoring Rubric:
    • 9-10 points: Student who has grasped the concepts in lessons 1-9.
    • 7-8 points: Average student. Should work on concepts in problems missed.
    • 5-6 points: Student who has missed some major concepts. Needs help in areas not understood. What you do here depends on whether the student's work exhibits sloppy computation or misunderstood concepts.
    • Below 5: a 'lost' student. Probably has not been turning in homework. Retention in this program (or steps to get homework turned in) should be a discussion topic with student and parents. Remember, this is the student that you can damage mathematically by dragging them through more complex topics in the months to come.
  3. (10 min) Introduce negative numbers:
    1. Draw this number line on the board:
       |---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
      -7  -6  -5  -4  -3  -2  -1   0   1   2   3   4   5   6   7   8   9
      
    2. Pass out the Negative number handout and follow the discussion and examples in the handout.
    3. Get students to come to the board to solve these problems:
      • -2 + 8 (when results are positive, get students to put "+" signs on them)
      • +5 - 10
      • +2 - 5
      • -4 - 3
    Use the terminology "Start at [first number] and move [left/right] [second number] places".
  • (Remainder of class) In-class Exercise.
  • Hand out homework as students successfully complete the in-class exercise.